Dryness sensor assembly

ABSTRACT

A bridging-type sensor assembly for use in domestic laundry dryer wherein a pair of sensing elements having leg portions extending through an insulating mounting base and through a bulkhead of a drying chamber for engagement by resilient clips which secure the sensing assembly onto the bulkhead. At least one of the clips is provided with means for biting into the bulkhead to provide an electrical ground for the sensing element that it is engaging and the leg portion of the other sensing element is provided with a second insulating member to electrically insulate it from the bulkhead member.

United States Patent 1 3,593,571

[72] In n r Jay A. Wiechert 2,473,690 6/1949 Olson et al v i l 85/83 X Benton Harbor, Mich. 3,343,272 9/1967 Janke et al 34/45 [2H Appl. No. 847,361

[22] Filed Aug. 4, I969 [45] Patented July 20, I97! [73] Assignee Whirlpool Corporation Benton Harbor, Mich.

Primary Examiner-Richard C. Queisser Assistant Examiner-Ellis J. Koch Attorney-Hill, Sherman, Meroni, Gross & Simpson [54] DRYNESS SENSOR ASSEMBLY 6 Claims, 9 Drawing Figs.

[52] US. CL 73/73, ABSTRACT; A brid ing ty e sensor assembly for use in 34/45 domestic laundry dryer wherein a pair of sensing elements [51] Int. Cl Gln /02, h in l portions extending through an insulating mounting I F26b l3/ b d through a bulkhead of a drying chamber for engage- Field oiSearch 73/73, 335, m b ili t li whi h secure the sensing assembly onto 3365; 324/61 My 65 M; 35/83; 34/45 the bulkhead. At least one of the clips is provided with means for biting into the bulkhead to provide an electrical ground for 1 [56] References (mad the sensing element that it is engaging and the leg portion of UNTED STATES PATENTS the other sensing element is provided with a second insulating 1,757,462 5/1930 Mack /8.3 member to electrically insulate it from. the bulkhead member.

PATENTED JUL2 0 |97l SHEET 1 [IF 3 SHEEI 2 0F 3 mmmmoml INVENTOR. JAY 14. Mac/lax? wZM a @W A'rrole/vzsyts' 1. Field of the Invention The present invention is directed to a sensing assembly for determining the moisture content of the material being dried in a domestic laundry drying apparatus.

2. Prior Art In drying material such as clothes in a home laundry clothes dryer, it is desirable to dry the clothes to a particular .point of dryness or until they contain a certainpercentage of moisture. Therefore it has been proposed to provide sensing means in the clothes dryer to determine the degree of dryness and to stop the drying action once a predetermined amount of dryness has been reached. An example of such a sensing device for controlling the drying operation is disclosed and claimed in the U.S. Pat. No. 3,343,272 assigned to the assignee of the present invention. The drying chamber is a rotating drum provided with a sensing means comprising spaced sensing ele ments or electrodes, one of which is grounded to the apparatus and the other of which is insulated from grounding to the apparatus and connected to a control circuit. The pair of electrodes determine the dryness of the clothes by measuring the resistance of the clothes as a function of the amount of moisture contained in the clothes or material being dried.

Another example of a dryness sensing device is disclosed in the U.S. Pat. No. 3,391,468 also assigned to the same assignee as the pres nt invention. The drying chamber has a rotating drum having a seal with a fixed bulkhead at the rear of the drum. The sensing device is mounted on the fixed bulkhead adjacent to the outlet vent of the drying chamber. Due to the rotation of the rotating drum, the clothes move past and into contact with the sensing device after being subjected to the drying action of the hot airflow. Since the sensing means is placed upstream of the travel of the clothes in the drum with respect to the outlet, the airflow through the outlet draws the clothing toward and into contact with thesensing element.

SUMMARY OF THE INVENTION The present invention is a sensing device having sensing elements mounted on an insulating base means with a leg portion of each of the elements extending through the base means and the support member of the apparatus with clip means engaging the leg portions to secure the elements and the insulating base means on the support member. One of the leg elements receives means to prevent electrical grounding of the element bite into the support member to facilitate electrical grounding.

REFERENCED PATENT The disclosure of U.S. Pat. No. 3,391,468 is incorporated by reference.

AS SHOWN ON THE DRAWING:

FIG. 1 is a front elevational view of the stationary bulkhead of a dryer having a sensor assembly of the present invention mounted thereon;

FIG. 2 is a cross-sectional view taken along the lines IIlI of FIG. 1;

FIG. 3 is an isometric view of one of the sensing elements removed from the assembly;

FIG. 4 is a cross-sectional view along line IV-IV of FIG. 1;

FIG. 5 is an isometric view of a clip means removed from the sensing device;

FIG. 6 is an enlarged plan view of an embodiment of the sensing assembly;

FIG. 7 is a cross-sectional view taken alonglines VII-VII of FIG. 6;

FIG. 8 is a side view ofa sensing element utilized in the embodiment ofFIG. 6; and

FIG. 9 is an enlarged isometric view of the clip means utilized in the embodiment of FIG. 6.

AS SHOWN ON THE DRAWINGS Although the principles of the present invention are of utility in and dryer construction, a particularly useful application is made to dryers for fabrics and the like. The features and advantages of the'invention will be readily apparent from the following description of certain preferred embodiments thereof taken in conjunction with the accompanying drawings although variations and modifications may be effected without departing from the spirit and scope of the concepts of the disclosure.

Referring to FIG. 1, a bulkhead is indicated generally at 36 which is adapted to be located in the rear of a drum as shown in referenced U.S. Pat. No. 3,39l,468.ln particular, reference is made to FIGS. 1--4 and columns 2, 3 and 4.

Means are provided for sensing the wetness of the tumbling fabrics, that is, the amount of moisture remaining in the fabrics. The wetness sensor comprises a pair of electrodes stationarily situated within the confines of the drum 24 and openly engageable with the fabrics tumbling therein. As the fabrics temporarily bridge the gap between the two stationary electrodes, the amount of moisture in the fabrics is sensed as a functional electrical conductivity in a control circuit of which the electrodes and the fabrics constitute a part.

In accordance with the principles of the present invention a sensing assembly or wetness sensor is indicated at 54 andis securely fastened to the inner face or side 36a of the stationary bulkhead 36.

The sensor assembly 54 is characterized as comprising a pair of electrodes or sensing elements 56 and 57 disposed on a base means or member 58 of insulating material.

As best shown in FIG. 3, the sensing element 56 has a body portion 59 with a leg portion 60 extending at an angle thereto. At the opposite end the leg portion 60 is a second leg portion or tab 62 which is of a shorter length. In this embodiment the tab 62 is provided with barbed portions such as 63 which are struck from thetab 62, to facilitate the mounting of the element 57 in the block means 58. The leg portion 60 is provided with a slo 64 forming an abutment surface or shoulder 65 for engagement by the clip means 66. The shoulder or abutment surface is adjacent the terminal end portion which has an aperture 67 and a pointed end to form a spade or knife contact for receiving an electrical connector for attaching the sensing element 56 into the electrical control circuit such as that illustrated in U.S. Pat. No. 3,343,272. The body portion 59 of the sensing element has a raised deformed or channel portion 68 as best illustrated in FIG. 4. l

The other sensing element 57 has a body portion similar to 59, a tab 69 at one end and a leg portion 70 at the other end which is substantially the same as the leg portion 60 but it is not provided with the knife or spade contact portion. As seen in FIG. 2, the leg portion 70 is at the opposite end of the body portion 59 and the tab 69 of the sensing element 57 will be at the end of where the leg portion 60 is on the sensing element 56.

The base member 58 which is made of insulating plastic has an inclined or contoured surface 71 which is provided with a positioning means including grooves 72: and 73 for receiving the sensing elements 56 and 57 respectively as best illustrated in FIG. 4. The depth of the grooves 72 and 73 are such that the raised portion 68 of each of the sensing elements 56 and 57 which are inclined to conform to the surface 71 is disposed above the surface 71 for contact with the clothes in the drying apparatus.

The base means 58 is provided with a pair of projecting legs or mounting post 74 and 75 with the leg or post 75 having a portion 76 which is received in an aperture or opening 77 in the support member or bulkhead 36. The positioning means for each of the sensing elements includes the groove such as 73 which ends at one end with a recess and at a the other end with a passageway. As illustrated, the groove 73 terminates in a recess 78 for receiving the tab 69 and a passageway 79 which extends through the post 74. The sensing element 57 is mounted on the base member 58 with the body portion 59 received in the groove 73, the leg portion 70 extending through the passageway 79 and extending outward of the opposite side 36b of the support member or bulkhead 36. The element 56 is mounted in a similar way with its tab 62 in its respective recess and its leg portions 60 in a passageway 80 extending through the post 75 and the extension 76.

To secure the sensing device 54 on the bulkhead 36, clip means 66, which are illustrated as being wire members bent into an acute angle, having leg portions 81 and 82, are inserted in the slots such as 64 and engage the shoulder or abutment 65 to urge the shoulder or abutment away from the side 36b of the bulkhead 36. The leg 81 is provided with a bent portion 83 forming a depression which receives the abutment surface and provides a shoulder to prevent the removal of the clip which is resiliently urging the shoulder or abutment outward from the bulkhead 36. The leg portion 82 terminates in the bent portion 84 providing a cutting edge for digging into the surface 361: to

remove paint or rust and penetrate into the surface 36b to insure a good contact to facilitate grounding of the sensing element 57.

In order to prevent the grounding of the sensing element 56, an insulating means 85 which is a block having an aperture to receive the leg portion 60 is telescopically received thereon and cooperates with the extension 76 to prevent electrical contact between the leg portion 60 and its respective clips 66 with the bulkhead member 36.

To facilitate handling of the clips 66, the portion 81 terminates in a circular bend 86 to provide means for grasping the clip member.

The embodiment of FIGS. 25 utilizes a sensing element formed from a strip of metal and the resistant clip means 66 which is formed from spring tempered wire. As can be seen, the sensing means 54-comprises a pair of clips, a pair of sensing elements, a base member, and an insulating member. Due to the resilient nature of the clips 66, the sensing device may be mounted on the bulkhead 36 in a simple procedure of assembling the elements onto the base 58 with the leg portions through apertures of the bulkhead walls and then applying the insulating means 85 on the one sensing element and inserting the resilient clips 66. The device can easily be connected to the electrical control circuit by slipping on the connector sleeve on the spade formed on the terminal portion of leg 60 of the sensing element 56.

In FIGS. 6-9, another embodiment shows a sensing device 88, with sensing elements 90 and 91 disposed on an insulating base member or means 92. The element such as 90, which is best illustrated in FIG. 8, is formed of a rod or wire member having a body portion 93 which is provided with a bend of approximately between the body portion 93a and 93b and has a leg portion 94 extending angularly from the body portion 93b. At the opposite end, the body portion 93a has a'tab or short leg portion 95. The leg portion 94 is provided with a cut portion which can either be a circular groove 96 or a pair of opposed grooves to form an abutment surface or shoulder 97.

The base member 93 has a contoured or inclined surface 98 which conforms to the body portion 93 and has a pair of supporting posts 99 and 100, with the post 100 having an extension 101 for being received in an aperture formed in the bulkhead wall or support member 36. The base member 92 is provided with positioning means for each of the electrodes or elements 90 and 91. The positioning means includes a groove such as 102 terminating at one end in the recess such as 103 and at the other end in a passageway such as 104. As illustrated the groove 102 is a depth so that a portion of the body portion 93 extends above the surface 98.

. When the base means 92 is mounted on the side 36a of the bulkhead or support member 36 with the extension 101 of post extending through the aperture, the electrodes 90,91 are inserted with their leg portions extending through their respective passageways and projecting from the opposite side 36b of the bulkhead 36. To prevent the leg 94 of the electrode 90 from coming into contact with the bulkhead, an insulating means 106, which is illustrated as a block, is telescopically received on the leg portion extending through the bulkhead. To secure the sensing elements 90 and 91 on the base member 92 and to hold the base member against the bulkhead 36, clip means 108 and 109 are provided and engage the abutment surfaces or shoulders 97 of the respective leg portions to sensing elements 90 and 91.

The clip means 108 and 109 are a piece of flat metal bent at 110 into an acute angle to provide a pair of straight portions such as 111 and 112 best illustrated in FIG. 9. The clip members are each provided with a slot 113 which has a narrow slot portion 114. The slot portion 114 is adapted to engage the abutment surfaces 97 while the slot 113 is ofa width to receive the full diameter of the leg portion 94. Both of the clips 108 and 109 are provided with an S-bend 115 to provide a shoulder for engagement by the edge of the abutment surface 97 to prevent the withdrawal of the clips from engagement after their insertion.

As best illustrated in FIG. 7, the clip 109 acts between the bulkhead 36 and abutment surface 97 of the leg element of the electrode 91 while the clip 108 acts between the abutment surface 97 and the insulating block 106. To facilitate electrical connection of the sensing element 90 to a control circuit, the clip 108 is provided with a spade portion 116 for receiving an electrical connector. To facilitate the grounding of the element 91 to the support means or bulkhead 36, the clip 109 is provided with bent down tab portions 117, 117, as best illustrated in FIG. 9 to facilitate biting into the surface or side 36b through the paint, rust and any other accumulation of material or dirt.

As in the previously described embodiment, the clips 108, 109 allow the rapid insertion or installation by a simple procedure of the sensing means or device onto the bulkhead of the dryer assembly. The contour of the surface of the base means 92 insures the spreading and smooth flow of the material which is moving across the sensing elements 90 and 91 so that the amount of resistance due to the moisture in the clothes can be measured to determine the degree of dryness of the clothes being dried in the clothes dryer.

Although various minor modifications might be suggested by those versed in the art, it should be understood that I wish to employ within the scope warranted hereon, all such embodiments as reasonably and properly come within the scope of my contribution to the art.

The embodiments of the invention in which I claim an exclusive property or privilege are defined as follows:

1. In a sensing device for determining a dryness of a material being dried in a drying chamber of a drying device, said sensing device having at least two sensing elements mounted in spaced relationship on a surface of a base member of insulating material adapted to be mounted by fastening means on a support member of the drying chamber with a projection of the base member extending into an opening therein, and the sensing device having means for connecting the sensing elements to a sensing circuit, the improvements comprising:

each of the sensing elements having a first leg portion extending angularly from one end of a body portion thereof, each of said first leg portions having a length to extend through the base member and the support member and terminating in an abutment surface,

each of said sensing elements having a second leg portion extending angularly from the outer end of the body portion of the sensing element in the same direction as the first leg portion, each of said second leg portions being shorter than the first leg portion,

said base member having a recess on the surface to receive each of the second leg portions and having a passage therethrough to receive each of the first leg portions with one of the passages extending through the projection,

resilient clip means for engaging each of the abutment surfaces of each sensing element, said clip means and abutment surfaces coacting to provide means for mounting the sensing device on the support member, and

said first and second leg portions of each sensing element coacting with the passage and recess of the base member respectively, to form means for mounting the sensing elements on the base member.

2. In a sensing device according to claim I, wherein each of said resilient clip means is a member bent into a V-configuration having legs interconnected by an acute portion to provide a resilient wedge.

3. In a sensing device according to claim 2, wherein the leg portion of the clip engaging the abutment surface is provided with a bend defining a shoulder for engagement with the abutment surface of the sensing elements so that while the resilient clip is compressed by its engagement with the abutment surface, the shoulder coacting with the sensing element prevents the movement of the abutting surface toward the acute angle bent portion of the clip.

4. In a sensing device according to claim 1, wherein the means for connecting the sensing element to the sensing circuit includes means for electrically connecting one of the sensing elements to the support member of the drying chamber and at least the resilient clip means engaging said one sensing element includes means for biting into the surface of the support member to facilitate the electrical connection of said one sensing element thereto.

5. In a sensing device according to claim 1, wherein the means for mounting the sensing element includes a groove in the surface of the base member extending from each passage to its respective recess to receive the body portion of the sensing element, said groove having a depth so that a portion of each of the sensing elements received therein extends above the surface of the base member.

6. In a sensing device for detennining a dryness ofa material being dried in a drying chamber of a drying device, said sensing device having at least two sensing elements mounted in spaced relationship on a surface of a base member of insulating material adapted to be mounted by fastening means on a support member of the drying chamber with a projection of the base member extending into an opening therein, and the sensing device having means for connecting a sensing element to a sensing circuit, the improvements comprising:

each of the sensing elements having a first leg portion extending angularly from one end ofa body portion, each of said first leg portions having a length to extend through the base member and the support member with the free end of the first leg portion terminating in an abutment surface; each of the sensing elements having a second leg portion extending angularly from the other end of the body portion in the same direction as the first leg portion, each of said second leg portions being shorter than the first leg portion; said base member having grooves in spaced relationship on said surface thereof, each groove: terminating at one end in a recess into the surface to receive each of the second leg portions and each of said grooves terminating at the other end in a passage through the base member to receive each of the first leg portions with one of the passages extending through the projection, resilient clip means for engaging each of the abutment surfaces of each of the sensing elements, said clip means and abutment surface coacting to provide means for mounting the sensing device on the support member, and said body portion and first and second leg portions of each of said sensing elements coacting with the groove, passage and recess of the base member respectively, to form means for mounting the sensing element on the base member.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,593,571 Dated July 20, 1971 Inventor(s) Jay A. Wiechert It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 11, --angle-- should be inserted after "acute".

Column 6, line 29, "surface" should read --surfaces--.

Signed and sealed this L th day of January 1972.

I (SEAL) Attest:

EDWARD M.F'LE'I'CHER,JR. R BERT GOTTSCHALK Attesting Officer Acting Commissioner of Patents 

1. In a sensing device for determining a dryness of a material being dried in a drying chamber of a drying device, said sensing device having at least two sensing elements mounted in spaced relationship on a surface of a base member of insulating material adapted to be mounted by fastening means on a support member of the drying chamber with a projection of the base member extending into an opening therein, and the sensing device having means for connecting the sensing elements to a sensing circuit, the improvements comprising: each of the sensing elements having a first leg portion extending angularly from one end of a body portion thereof, each of said first leg portions having a length to extend through the base member and the support member and terminating in an abutment surface, each of said sensing elements having a second leg portion extending angularly from the outer end of the body portion of the sensing element in the same direction as the first leg portion, each of said second leg portions being shorter than the first leg portion, said base member having a recess on the surface to receive each of the second leg portions and having a passage therethrough to receive each of the first leg portions with one of the passages extending through the projection, resilient clip means for engaging each of the abutment surfaces of each sensing element, said clip means and abutment surfaces coacting to provide means for mounting the sensing device on the support member, and said first and second leg portions of each sensing element coacting with the passage and recess of the base member respectively, to form means for mounting the sensing elements on the base member.
 2. In a sensing device according to claim 1, wherein each of said resilient clip means is a member bent into a V-configuration having legs interconnected by an acute portion to provide a resilient wedge.
 3. In a sensing device according to claim 2, wherein the leg portion of the clip engaging the abutment surface is provided with a bend defining a shoulder for engagement with the abutment surface of the sensing elements so that while the resilient clip is compressed by its engagement with the abutment surface, the shoulder coacting with the sensing element prevents the movement of the abutting surface toward the acute angle bent portion of the clip.
 4. In a sensing device according to claim 1, wherein the means for connecting the sensing element to the sensing circuit includes means for electrically connecting one of the sensing elements to the support member of the drying chamber and at least the resilient clip means engaging said one sensing element includes means for biting into the surface of the support member to facilitate the electrical connection of said one sensing element thereto.
 5. In a sensing device according to claim 1, wherein the means for mounting the sensing element includes a groove in the surface of the base member extending from each passage to its respective recess to receive the body portion of the sensing element, said groove having a depth so that a portion of each of the sensing elements received therein extends above the surface of the base member.
 6. In a sensing device for determining a dryness of a material being dried in a drying chamber of a drying device, said sensing device having at least two sensing elements mounted in spaced relationship on a surface of a base member of insulating material adapted to be mounted by fastening means on a support member of the drying chamber with a projection of the base member extending into an opening therein, and the sensing device having means for connecting a sensing element to a sensing circuit, the improvements comprising: each of the sensing elements having a first leg portion extending angularly from one end of a body portion, each of said first leg portions having a length to extend through the base member and the support member with the free end of the first leg poRtion terminating in an abutment surface; each of the sensing elements having a second leg portion extending angularly from the other end of the body portion in the same direction as the first leg portion, each of said second leg portions being shorter than the first leg portion; said base member having grooves in spaced relationship on said surface thereof, each groove terminating at one end in a recess into the surface to receive each of the second leg portions and each of said grooves terminating at the other end in a passage through the base member to receive each of the first leg portions with one of the passages extending through the projection, resilient clip means for engaging each of the abutment surfaces of each of the sensing elements, said clip means and abutment surface coacting to provide means for mounting the sensing device on the support member, and said body portion and first and second leg portions of each of said sensing elements coacting with the groove, passage and recess of the base member respectively, to form means for mounting the sensing element on the base member. 